Calcium‐ferrum‐alumina‐silicate (CFAS) corrosion behavior of Lu₄Hf₃O₁₂ ceramics at 1400°C

Abstract

In this work, the corrosion behavior of rare‐earth Lu4Hf3O12 ceramic when exposed to a CaO‐FeO1.5‐AlO1.5‐SiO2 (CFAS) environment at a temperature of 1400°C was investigated, with a focus on exploring the associated phase transformation, microstructure evolution, and corrosion reaction mechanism. Results reveal that during the corrosion process, the CFAS melt infiltrates Lu4Hf3O12 particles through cracks, resulting in the formation of a continuous reaction layer. This reaction leads to the generation of several high‐melting‐point garnets, including HfO2, Lu3Al5O12, Ca3Fe2(SiO4)3 (Ca‐Fe garnet), and Ca3Al2Si3O12 (Grossular). These garnets effectively fill the voids within the Lu4Hf3O12 ceramics, preventing further infiltration of the CFAS melts. As time progresses, the rate of the reaction gradually increases, while the rate of infiltration consistently decreases. Consequently, a relatively stable corrosion layer is achieved, effectively impeding further corrosion.